摘要
A thermally induced hexagonal close-packed(HCP)to face-centered cubic(FCC)phase transition was investigated in anα-type Ti35 alloy with twinned structure by in situ heating transmission electron microscopy(TEM)and ab initio calculations.TEM observations indicated that the HCP to FCC phase transition occurred both within matrix/twin and at the twin boundaries in the thinner region of the TEM film,and the FCC-Ti precipitated as plates within the matrix/twin,while as equiaxed cells at twin boundaries.The crystallographic orientation relationship between HCP-Ti and FCC-Ti can be described as:{111}FCC//{0002}HCP and<110>FCC//<1210>HCP.The HCP to FCC phase transition was accomplished by forming an intermediate state with a BB stacking sequence through the slip of partial dislocations.The formation of such FCC-Ti may be related to the thermal stress and temperature.Ab initio calculations showed that the formation of FCC-Ti may also be related to the contamination of interstitial atoms such as oxygen.
基金
supported by the Natural Science Foundation of Shanghai(Grant No.21ZR1445100)
the National Natural Science Foundation of China(Grant No.52271108)
the Foundation of Xi'an Key Laboratory of High-Performance Titanium Alloy(Grant No.NIN-HTL-2022-02)
financial support from the Frontier and Key Projects of the Chinese Academy of Sciences(Grant No.QYZDJ-SSW-JSC031-01)
financial support from Xi’an Science and Technology Plan Project(Grant No.2020YZ0028).
